Development and validation of a work-related risk score for upper-extremity musculoskeletal disorders in a French working population

Objectives The aim of this study was to develop an easy-to-use risk score based on occupational factors and to validate its performance to identify workers either having (diagnostic setting) or developing (prognostic setting) upper-extremity musculoskeletal disorders (UEMSD).Methods This study relied on data from the Cosali prospective cohort conducted in a French working population. Diagnostic status for six UEMSD at inclusion and at follow-up was assessed by a standardized clinical examina-tion. Occupational factors were collected through a self-administered questionnaire completed before the clinical examination at inclusion. The risk score was derived from a multivariate penalized logistic regression model on data of 2468 workers included in 2002-2003 (323 UEMSD cases), and the diagnostic validation of the score was performed using data of 1051 workers included in 2004-2005 (126 UEMSD cases). The score's performance for predicting UEMSD at follow-up in workers without UEMSD at baseline was then assessed.Results The risk score includes physical, psychosocial and organizational factors at work. In the diagnostic validation sample, it had acceptable calibration and discrimination performance for UEMSD at baseline, with a relatively low area under the ROC curve (AUC) (0.60, 95% confidence interval 0.57-0.63) and a high negative predictive value (89-90%). The baseline risk score showed similar performance in prognostic setting.Conclusion This UEMSD risk score was developed with the purpose to stratify work situations and prioritize those requiring intervention by an ergonomist. Further external validation studies are required to confirm its predictive performance and determine its practical utility as a first-line risk assessment tool, especially among working populations with higher prevalence of UEMSD.